Influência do treinamento de força na atividade da esfingomielinase ácida e da inflamação na infecção experimental por Trypanosoma cruzi

Abstract

Trypanosoma cruzi is a hemoflagellate protozoan capable of invading mammalian cells and inducing acute and/or chronic immune responses associated with pathological alterations in different tissues, particularly contributing to adverse cardiac remodeling. In contrast, resistance training promotes neural and muscular adaptations and positively influences skeletal and cardiac muscle remodeling. In this context, acid sphingomyelinase (ASM) is an enzyme responsible for cleaving sphingomyelin in the plasma membrane and plays a role in the regulation of the inflammatory response and, consequently, in muscle remodeling. Thus, this study evaluated the effectiveness of resistance training and ASM regulation on the inflammatory response in mice infected with the Colombian strain of T. cruzi. Male C57BL/6 mice (n = 76) were submitted or not to an 8-week ladder-based resistance training protocol and treated or not, during the chronic phase of experimental infection, with amitriptyline hydrochloride (5 mg/kg), a functional inhibitor of ASM. After euthanasia, blood samples and heart and skeletal muscle (gluteus) tissues were collected for assessment of ASM activity, histological alterations, and quantification of TNF, IFN-γ, IL-10, and IL-17A. An increase in maximal strength was observed in trained animals, both non-infected and infected, and a longer climbing time was observed in infected animals, regardless of treatment. In the heart, resistance training reduced TNF, IFN-γ, and IL-17A production in infected animals, with or without amitriptyline treatment. In skeletal muscle, resistance training and ASM inhibition reduced TNF and IFN-γ levels in infected animals. No differences were observed in IL-10 levels in either tissue. ASM activity was higher in infected animals and was further increased in the cardiac muscle of the infected and trained group, while it was reduced in the skeletal muscle of amitriptyline-treated animals. Histological analysis of skeletal muscle revealed a greater inflammatory infiltrate in infected groups, with no increase in fiber diameter in trained groups. In conclusion, resistance training promoted a favorable modulation of the inflammatory response during chronic T. cruzi infection, while ASM activity exhibited tissue-dependent effects.